Cigarette smokers prone to depression have difficulty quitting smoking. Several studies have tested whether depression-prone smokers in particular would benefit from adaptations of cognitive behavior therapy (CBT) of depression, with mixed results. This research program tests possible explanations for these mixed results. An initial AREA grant (1 R15 CA77732-01 "Cognitive Coping and Depression Among Cigarette Smokers") found that depression-vulnerable smokers do lack the cognitive coping skills ostensibly taught in CBT. This proposal is for a competing continuation of this R15 grant. A pilot study will be conducted to assess whether group cognitive behavior therapy (a) is effective, relative to a contact-time-equivalent comparison condition, in achieving abstinence at three-month follow-up; (b) is especially effective for depression- prone smokers; and (c) remediate the cognitive coping skills identified in the earlier project as impaired among depression-prone smokers. Several alternative mediating mechanisms of CBT effects (acceptance, dichotomous thinking, outcome expectancies for smoking) will also be evaluated. 240 regular smokers will be randomized to one of two eight-session group treatments: (a) Cognitive Behavior Therapy & Education & Scheduled Reduced Smoking; or (b) Education & Scheduled Reduced Smoking alone. Depression vulnerability will be measured before treatment, and the potential mediators of CBT effects will be measured before and after treatment. Smoking status through three-month follow-up will be assessed, with expired air CO corroboration of self-reported abstinence. This pilot study will help establish plausible effect sizes, and therefore planned sample size, for a future randomized clinical trial of the moderation and mediation of CBT effects for smokers, which will incorporate a longer follow-up period. Therapists will be graduate students trained by the principal investigator. Undergraduate students will rate a subjectively scored coping measure as well as the adherence and differentiability of treatment conditions, based on therapy session tapes.